Hypodermic syringe.



N0. 767,686. PATENTED AUG. 16, 1904.

H. J. DBTMERS. HYPODBRMIG SYRINGE.

NO MODEL.

WITNESSES! INVENTOR WW %22 :z Jflemens' @%;MQQMW ATTORNEYS UNITED STATES Patented August 16, 1904.

HENRY J. DETMERS, OF COLUMBUS, OHIO.

HYPODERIVIIC SYRINGE.

SPECIFICATION forming part of Letters Patent No. 767,686, dated August 16, 1904. Application filed December 9, 1908. Serial No. 184,380. (No model.)

To all whom it may concern:

Be it known that I, HENRY J DETMERs, a citizen of the United States, residing at O0- lumbus, in the county of Franklin and State of Ohio, have invented a certain new and useful Improvement in Hypodermic Syringes, of which the following is a specification.

My invention relates to the improvement of' hypodermic syringes, and has particular relation to theimprovement of the construction which is the subject of Letters Patent No. 600,803, dated March 15, 1898, and issued to Stillman WV. Robinson and myself.

The objects of my present invention are to provide a hypodermic syringe of such improved construction and arrangement of parts as to facilitate the retention of the same in a clean and asceptic condition, to provide an improved needle-holding cap for the plungercontaining barrel of such construction and arrangement of parts as to facilitate the connection of the needle with the barrel in such manner as to prevent any tendency of the needle or its supporting-cap dropping out or working away from its proper position and to insure a direct contact of the end of the plunger with the inner end of the needle and its holder when the plunger is moved inwardly to its limit, and to produce other improvements, the details of construction of which will be more fully pointed out hereinafter.

These objects I accomplish in the manner illustrated in the accompanying drawings, in which Figure 1 is a central longitudinal section of my improved syringe-barrel and needle-holding cap, showing the needle and plunger therein in elevation. Fig. 2 is an enlarged inner end view of the needle-carrying cap, and Fig. 3 is a longitudinal section of said cap.

Similar numerals refer to similar parts throughout the several views.

1 represents the barrel or cylinder, which may be formed of metal or other suitable material, this barrel being provided at its outer end with peripheral threads, as indicated at 2. This screw-threaded end ofthe barrel is adapted to be received, as shown, by the internallythreaded inner end socket portion of a preferably-tapering cap or hub body 3, said capbody being formed with acentral bore or passage extending throughout its length, which tapers slightly toward its outer end. Within said central cap-bore is fitted removably a correspondingly-shaped needle-shank or internal hub i, the latter being formed with an extended outer end portion a, which is externally threaded and which is adapted to receive a suitable form of internally-threaded nut 5, the inner side of which abuts against the outer and smaller end of the cap-body 3. Through the hub or shank t extends the inner portion of the usual hollow or tubular syringe-needle 6, said needle being rigidly secured by brazing or otherwise within the hubbody 4 and the inner end of said needle being flush with the inner end of the hub or shank and the inner end of the latter likewise flush with the inner end of the cap-body.

Slidably fitting within the hollow or bore of the barrel 1 is a plunger 7 the latter preferably being of' uniform diameter throughout its length and so accurately formed and fitted within the barrel as to permit of its movement longitudinally therein without the admission of air between its periphery and the inner surface of said barrel. The outer end of the plunger is provided with a suitably-formed enlargement in the nature of a thumb-head, as indicated at 8, and the body of the plunger is formed throughout the greater portion of its length with continuous circumferential grooves or markings of slight depth, these grooves, as set forth in said former patent, serving the double purpose of graduations to determine the quantity of liquid drawn into or expelled from the barrel and to form a barrier to the passage of air between the barrel and plunger. i

The method of using hypodermic syringes of this class is so well known as to obviate the necessity of explanation; but it will be observed that when the plunger is moved to its innermost position the surface of its inner end is in direct contact with the inner end of the cap 3, the needle-hub 4:, and the needle 6, thereby leaving no spaces or interstices at the inner end of the barrel Where dirt, bacteria, or foreign matter may lodge or collect and insuring a complete discharge of the fluid into and through the needle Without air-bubbles. When it is desired to remove the needle, it Will be understood that the cap 3 may be readily unscrewed from the barrel, the nut 5 unscrewed from the threaded end of the hub 4, and the needle and its holder permitted to drop from the larger end of the cap-bore, thus permitting of the employment of interchangeable needles.

From the construction disclosed it Will be understood that a simple and reliable hypodermic syringe is provided, the parts of which are so arranged as to permit of their being retained in a thoroughly clean and asceptic condition.

Having noW fully described my invention,

What I claim, and desire to secure by Letters Patent, is

In a hypodermic syringe, the combination with a barrel and a plunger slidably fitting Within said barrel, of a hub having an internally-threaded socket portion engaging external threads of said barrel, said hub having a tapering central passage, a tapering needleholding hub removably contained Within said hub-passage and having a threaded outer end extension, a hypodermic needle secured Within and extending through said hub and a nut adapted to be screwed on the threaded exten sion of the hub, the inner ends of said hub,

hub and needle being flush With the end of the 3 5 barrel.

HENRY J. DETMERS. In presence of O. C. SHEPHERD, A. L. PHELPS. 

